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On-line version ISSN 1678-4677
EIRAS, Marcelo et al. Characterization of a non-L3 gene-resistance breaking Pepper mild mottle virus isolate in Capsicum. Fitopatol. bras. [online]. 2004, vol.29, n.6, pp. 670-675. ISSN 1678-4677. http://dx.doi.org/10.1590/S0100-41582004000600014.
A strain of Pepper mild mottle virus (PMMoV) was identified by biological and serological analysis of pepper (Capsicum baccatum) 'Dedo de Moça' seeds from São Paulo, SP, Brazil. To confirm these results, RT-PCR was performed with specific primers flanking the coat protein (CP) ORF of tobamoviruses in subgroup 1. The DNA-amplified fragments, when sequenced and compared with other tobamovirus CP sequences stored in the GenBank, showed nucleotide similarity between 94 to 100% with other PMMoV CP sequences, and below 75% with the subgroup I tobamovirus species (Tobacco mosaic virus, Tomato mosaic virus and Odontoglossum ringspot virus) and 65% with species in the subgroups II and III. The Brazilian isolate showed 100% identity with a Japanese isolate, strongly suggesting that this pathogen could have been introduced from that country. This fact confirms the importance of the isolate's characterization, in order to establish adequate control measures to guarantee healthy seed interchange and to avoid the introduction and spread of tobamoviruses into new growing areas. The deduced CP aminoacids sequence showed that the PMMoV-BR was not capable to overcome L3 gene resistance. This fact was confirmed by the inoculation and reaction of differential Capsicum species. The Brazilian isolate was not able to infect C. chinense (L3) and C. chacoense (L4).
Keywords : Tobamovirus; pimenta; pimentão; seqüenciamento.